Method of and apparatus fob cutting worm gearing



S. L CONE Nov. 1, 1832.

METHOD OF AND APPARATUS FOB CUTTING WORM GEARING Filed May 2, 1927 5 Sheets-Sheet l nue'nfoz 5. C17/vf 5 Sheets-Sheet 2 A 1-... w .b r .u Wu

S. I. CONE METHOD OF AND APPARATUS FOR CUTTING WORM GEARING Filed May 2, 1927 Nov. l 1932.

NOV. 1, 1932. s, CCNE 1,885,686

METHOD 0F AND APPARATUS FOR CUTTNG WORM GEARING 5 Sheets-Sheet 5 Filed May 2, 1927 A-...mnllll I Nov l, 1932. s. l. coNE 1,885,686

Filed my g. 1927 5 sheets-Sheet 4 Nov. l, 1932. s. 1. coNE 1,835,586

HETHOD 0F AND APPARATUS FOR CUTTING WORM GERING 5 Sheets-Sheet 5 Filed lay 2. 192'? Patented Nov. 1, 1932 UNITED STATES SAMUEL I. GONE, OF NORFOLK, VIRGINIA, ASSIGNOR TO GONE WORM GEARING CORPORA- TION, OF NORFOLK, VIRGINIA, A CORPORATION OF VIRGINIA METHOD OF AND APPARATUS FOR CUTTING WORM GEARING Application led May 2, 1927. Serial No. 188,214.

Theoretically and practically the globoid gear is the most eiiicient type of worm gear but it has not been extensively used because of the lack of a rational method of generation. The methods of production heretofore in vogue not only were costly but resulted in gear elements of poor mating capacity'because the underlying principles were unsound. The practice in the main involved the adp. vance of the cutter or hob towards the blank, thus varying the distance between the axis of the cutter bar or hob and that of the blank, so that there was ro coordination between the cutters and the moving blank. And this lack of coordination resulted, in the early stages of the operation, in the cutting away of consid erable material which should not be removed.

The object of my invention is to obviate the disadvantages of the old practice and to se- 5 3 cure such coordination or harmony of motion of the generating instrumentalities and the blank as will admit of rapid and otherwise economical production of complemental globoidal ygear elements which are accurately 2.3 fitted or mated. Since the worm and Wheel are to operate with their respective axes relatively fixedor constant it follows that the same relationship should exist between the axes of the generating mediums of both ele- :3 ments. And so the nature of my invention consists in a system and means for maintaining fixed center distances of the mediums regardless of whether the generating operation involves the use of a cutter, grinder or hob, or

:5.3 a combination thereof, all of which is contemplated.

To enable others skilled inthe art to understand and practice the invention, I shall proceed to describe the same more or less in deu tail, reference being had to the accompanying drawings, wherein Figure 1 is a plan view of means exemplilied as a lathe attachment for generating the gears with cutting tools.

4s Fig. 2 is an elevation of the same.

Fig. 3 is a detail showing the path of cutting point at the beginning of cut.

Fig. 4 is a detail showing the path of cuttin point at close of cut.

ig. 5 is a plan partly in section of means for forming the thread gaps of the Worm by a cutting operation.

Fig. 6 is a vertical sectional View of the same.

Fig. 7 is a side view partly in section of a worm and its mate formed, in a continuation of my inventive thought, by a hobbinrr operation, the section being taken at the midplane.

Fig. 8 is an end view with the gear Wheel in section to show the relative curvature of contact, the section being taken on line 8-8 of Fig. 9 is an expanded section, taken on line 9 9 of Fig. 7, viewed laterally of the wheel and radially of its axis and showing the enY gagement of the gear teeth and worm threads.

Fig. 10 is a section through one of the worm threads taken on line 10-10 of Fig. 7.

Fig. 11 is a View partly in section of a hob in engagement with a formative gear Wheel, the section being taken at the mid-plane.

Fig. 12 is an end View of the hob.

Fig. 13 is a detail of the hob construction.

Fig. 14 is a sectional view of the initial or roughing operation.

Fig. 15 is a sectional view of the finishing operation as applied to the right flanks of the teeth.

Fig. 16 is a sectional view of the finishing operation as applied to the left flanks.

Generating by straight cutting the ar' soV tl right angles to the centerline of the cutting mechanism.

Carriage 9 is equipped with a circular table 10 mounted for rotation about its vertical axis and havin a finished horizontal upper sur- 10. face on which is mounted the wheel blank A.

The table 10 is rotated through the agency of a straight worm 11 meshing with a complemental gear element 12 formed or provided on the under part of the table. The worm is u driven by a shaft 13 supported in bearings 14 on the carriage 9. The worm is fixed with relation to the shaft and as the latter is capable of re ated longitudinal sliding movement in t e bearings 14, advantage may be '9U taken of such movement to provide for desirable alterations in the an ular position of the table 10 about its axis. his is accomplished throu h the medium of a hand wheel 15 having a ollow spindle 16 which accommodates the shaft and is in screw-threaded engagement with one of the bearings.- -The hand wheel thus affords a means of manual adjustment of the worm to insure a slight alteration in the angular osition of the table and therefore of the blau It will be understood that where conditions make it desirable the manual feed may be replaced by a suitable automatic feed without supplementing my inventive thought. It will be. further understood, of course, that suitable means either manual and/or automatic may be applied to the arbor or its equivalent, in order to impart the necessary change in angular position. The angular change 1s by preference obtained as indicated herein through the other axis of rotation; the reverse, however, may be emplolyed.

he driving shaft 13 is operated .by a gear train, generall indicated at 17, from a gear on the lathe c uck 18, the unit connected to the driving shaft having a spline connection 19 to provide for the longitudinal movement of the shaft necessary to the angular adjustment of the table. A

The carriage 9 may be moved towards or away from the cutting mechanism by means of a hand wheel 20 and screw spindle 21 operatively mounted with relation to the bed plate 8. Evidently, this adjustment of the carriage and connected parts is incidental to the setting up operation and is not desirable or possible after the gear train has been established.

A cutter bar 22 is terminally supported in `guide blocks 23 which are adapted and artively driven and similar and simultaneous movement is communicated to its mate at the tail stock end by a cross shaft 26 supported in housings 27 and equipped therein with pinions 28 meshing with the gear wheels 25.

The guide blocks 23 are in exact register so that the cutter bar is always parallel to or coincident with the axis of rotation of the cutting mechanism. The advance of the cutter bar is controlled by feed screws 29 which pass through the hubs of the gear wheels and have threaded engagement with the guide blocks, and are equipped at their outer ends with star wheels conventionally represented at 30. yPawls 31 are mounted in the housings in such way that they may simultaneously be extended into the paths of the star wheels. And a backin tension is maintained against the cutter ar by means of springs 32 disposed in sockets in the guide blocks and encircling the feed screws.

The cutter bar is provided with two end cutters 33 havin confronting and parallel cutting edges w ich .are equldistant about either side of a line passing through the axis of the table 10 and at right angles to the axis of rotation of the cutting mechanism. While two end cutters are shown it is manifest that one could be dispensed with by a cutting cycle which would take care of one set of flanks and afterwards the reverse iianks by either invertin the blank orby shifting the cutter to the ot er end of the' bar.

Initially the end cutters 33 are set to the shortest required radius and their cutting edges are alwa s set at 90 degrees to the centerline of the ar and, as the cutting operation progresses, the are advanced in a straight line. Mani estly each end cutter, as it passes through the blank, must cut a straight line radiating from the centerline of the bar and so enerate an angle on the formative tooth. his angle depends on the position of the cutter in relation Yto a4 line drawn at 90 degrees from the centerline of the cutter bar and intersecting the' center of the gear blank. Otherwise stated, the distance is yequal to the radius of a circle coaxial with the axis of the wheel, said circle being definitely fixed b the angle of the teeth when taken at the mi -plane. And this distance determines the half length of the worm with which the wheel is to'cooperate. All of these conditions having been predetermined and a proper ratio established as between the rate of rotation of the 'blank and the operation of the end cutters, through the system of gearing( described, it follows that thecutters can ma e no false or prematurecuts, but must definitely and accurately Igenerate teeth of predetermined an le and twist. This will be apparent upon re erence to the details, Figs. 3 and 4, showing, res ectively, the osition of an end cutter at the 4egnning an ending of the cutting operation,` the shaded portions representi t e areas traversed by the cutter. It will be noted that the axis Aof rotation of the cutters remains common to that of the worm, for which the gear is designed, throughout all the stages of the tooth cutting process. i

The use solely of the end cutters 33 gives satisfactory results in cases in which the lead of the worm threads is not very great but with increased helix and pressure angles it is of advantage to use additional cutters. Hence, by preference, secondary cutters 33 are employed for the removal of certain tooth material above and below the midplane which cannot be removed by the end cutters, socalled. And failure to remove such material might cause interference which would be at its maximum near the waist or middle of thevworm. Manifestly, "the edges of the secondary cutters are not disposed at right angles to' the axis of the cutter bar but at such angle thereto as iscalculated to bring them coincident with the desired tooth Hanks at the close of the cutter bar advance.

Uuttz'ag worm threads This work follows the saine general scheme of coordination of operations and constant center distance.

Referring to Figs. 5 and 6, the worm blank B is arranged to be operated on by a series of cutters 4 5, on a special holder capable of rotation at a speed in desired ratio with that of the blank. The cutters are disposed radially in a circular clamp or holder 46 mounted on a rotatable table 47, and they are advanced as required by a feed cone 48 operated by a screw 49. Another screw 50 is eiective to actuate the clamp to lock the cutters, and, of course, is released when the feed cone is to be actuated. It will be understood that the production of the worm is notl limited to the means described above but may'be also produced by changing the relative positions of a cutter and wormblank. An illustration would be to mount a cutter in place of the wheel blank indicated in Fig. l and replace the mechanismfindicated betweenlthe head and tail stock in the same ligure with a worm blank whose thread gaps had been previously roughed to a proximate size by any suit` able means. he feed required to widen the thread gapls and finish the flanks being imparted as erein illustrated by means of advancing or retracting the rotative position` of the table carrying the cutter by means of the hand wheel 15, Fig. 1 as heretofore described. In a word, the inventive thought residesin the production of either element by a scheme of coordination of operations and constant center distances. The feed be ing introduced as end cutting or side forming as by preference may .be adopted.

Generating by hobbz'ng The hob being a rapid cutting instrument due to the multiplicity of its cutting edges, it is evident that its use would be highly desirable for rapid and quantity production were it possible to obviate the disadvantages and deficiencies thatobtain under the usual hobbing practice. The principle underlying my inventive thought readily lends itself to the successful application of the hob as more fully will appear upon analysis of Figs. 7 8 and 9.

It `will be noted that the lines of the flanks of both theworm threads and wheel teeth as here illustrated are straight when taken at the midplane, and that, when projected inwardly of the wheel they are tangent to the circle W. The circle W is concentric with the wheel and its diameter is dependent upon the ultimate tooth angle Y. The diameter of the circle, therefore, becomes the working length of the Worm B', which length it is undesirable to reduce or impracticable to increase owing to certain interference or hooking which would develop at its ends.

- With uniform spacing of teeth, it follows that a tool or tools, having cutting edges coincident with the lines of the tooth flanks and operating in the midplane. will serve to develop the desired Worm thread flanks under the system of coordinated operations and maintenance of constant center distance already pointed out, and it is but a reversal of this procedure to produce complementary flanks on the mating wheel teeth by means of cutting edges lying within helical surfaces Common to those of the Worm thread Hanks. .Such an arrangement of cutting edges is found in the conventional hob possessing a form common to that of the Worm but its use is not practicable because of the unsatisfactory results of feeding it towards the wheel blank. f

Hence, the solution is to use hobs of relatively thin thread section and to generate in two stages. The first of these is a roughing operation, during which the hob with cutting edges arranged as shown in Fig. 13 is fed into the wheel blank until the predetermined or desired depth is reached; and the second is afilank finishing operation during which the center distance of the hob and wheel is always that of the finished worm and^worm wheel. The second operation may be edected by advancing and/or retracting the rotative position of either the wheel blank or the hob, the hob with cutting edges arranged as shown either in Fig. 11 or Fig. 13 may here be employed.

In a specific embodiment of the invention, the hob 51, Fig. 13, is designed to cut teeth to suit the worm B', Fig. 9, and has relatively thin threads 52. midplane shows the engagement of the Wheel The sectional view of the auA lil

tooth Hanks with those of the hob thread Hanks as at the beginning of the second or finishing step which involves the removal of metal between the tooth Hank lines a. b whereof the latter represents the finishing line. The center distances d are common, as are likewise the face and root lines'e f.

In the development of the Hanks of the thin hob threads, the procedure could be the same for each flank as that employed for the corresponding flank on the designed worm, the difference being that of its respective setting or adjustment about the core or inner body of the hob. These altered positions of the hob thread flanks are indicated by the dotted lines g, the angular shift being shown at h. This angle indicates the value of the retraction and advance in feed necessary 4during the finishing operation. Theshifting of the hob thread flanks presents in the midplane section a thread gap angle i differing.

from that of the designed tooth angle k. It will be observed, however, that the correspondinp' projection lines are tangent to the circle Referring to Fig. 9, it`will be noted that beginning with R5 the worm thread Hank contact with that of each succeeding wheel tooth flank widens in progressive order towards that shown at R. The cutting edges arranged along the flank of any corresponding hob thread when considered from left to right will each sweep over an increasing part of the tooth Hank, the final edge traversing the greatest arca and thus completing the tooth.

Referring to the detail, Fig. 13, it will be noted that the thread form is notched, as at 53, thus forming teeth 54. The Hank cutting edges 55 and face cutting edge 56 are established by relieving or sloping back the surfaces 57. A hob of the desired form and with cutting elements as just described is employed in the first or roughing stage, Fig. 14, which involves feeding the hob towards and into the blank. At the conclusion of the roughing operation or after the hob has been fed into the blank the required distance or to the relative positions shown in Fig.l 11, it is possible to proceed with the second or finishing operation with the same hob. But it is not always advantageous to use the one hob for both roughing and finishing forthe reason that its cutting edges are so arranged that it can act in only one direction of rotation,

which direction may be favorable for finish-.

ing tooth flanks directed one way, but unfavorable for finishing those facing the other way. For example, if the hob be substituted for the worm B in Fig. 9 and its cutting action be in the direction of the arrow M and the angular feed torque be applied in such manner as to set up the cutting pressure along the series of surfaces indicated by R', R, R, etc., the resulting cutting order would be unfavorable because the edges towards the leading end of the hob would perform the most of the work. If the angular feed torque be reversed the cutting pressure becomes active against the opposed Hanks of the wheel teeth or along the surfaces indicated by S', S, S, etc., and a reversal of cutting ordeil results,- an order in which as the work progresses each edge removes a more equable share of material.

Moreover, the precision nowrequired of the operation may only be maintained by replacing the hob employed for roughing with one calculated to remove a lesser quantity of metal. This second or finishing hob, as shown in Fig. 11, has cutting edges 58 along the thread Hanks only which are designed to cut in opposed directions as indicated by the arrows. Thus, referring again to Fig. 9, if the hob be substituted for the worm B and operated in the direction of the arrow M, the torque feed applied will create pressure along the surfaces at S', S2, S3,'etc., and the favorable cutting order will obtain along the left hand Hanks of the teeth. Similarly, if both the direction of rotation and that of the torque feed be reversed, a reversal or favorable cutting action will result along the opposed tooth Hank surfaces indicated at R', R2, R3, etc.

It is apparent that at all stages of the operation the lines of the thread andv tooth flanks, when taken at the midplane, will, if projected, be tangent to the basic circle W. This relation is maintained between the engaging thread and tooth Hank lines throughout the life of the gear and remains true re. gardless of the wear and accumulated backlash.

In the roughing operation, Fig. 14, the blank is fed towards the spindle. In the flank finishing operations, Figs. 15 and 16, there is no variation in the relative positions of the axis of the hob and that of the gear blank. It will be understood, of course, that one illustration of the means for producing wheels with thin hobs as described above would be to replace the mechanism between the head and tail stock as illustrated in Fig. 1 with the said hob conventionally secured thereto, and then by means of the hand wheel 15 and related mechanism therein described, effect the feed desired to widen the wheel tooth gap and finish the wheel tooth Hanks as previously described. Should it be desired to rough and finish with one operation the hand wheel 20, Fig. 1 would be, of course, utilized to produce the feed required for roughing and the wheel 15 for finishing either element.

The ends of the threads of the worm in practice are extended slightly and shaped, as

prising, in combination, blank supporting means and forming means rotatable on axes perpendicular to each other, means for changpendicular to each other, devices for actuatin same in predetermined timed relationship, devices for changing the relative rotao tive positions of the blank and former to effect the desired feed, and means for coordinating the said devices whereby the desiredflank form is imparted to said element while maintaining a fixed distance between the axes of rotation.

3. Apparatus for generating globoidal gearing, comprising, in combination, means for supporting a blank, means for supporting a former, devices for simultaneously rotating each of said means, means for advancing the former towards the blank during rotation by increasing its radial distance from its axis of rotation without altering the determined iixed distance between said axes.

4. Apparatus for generating globoidal gearing, comprising, in combination, means capable of ad]ustment for supporting a blank, means for supporting a former, devices for simultaneously rotatin each of said means oii axes that are perpen icular to each other, means for adjusting the blank support to establish a definite distance relationship of said axes, means for feeding the former into the blank by an increment of its radial distance from its axis' of rotation, and interrelated means for coordinating the operations of said devices whereby the gear forming operation is completed without the hazard of variation of the initial center distance.

5. Apparatus for generating globoidal gearing, comprising, in combination, means for rotatably supporting a blank, rotatable means for supporting a former whereby the plane of its cutting edge is parallel to and spaced apart from a plane passing through its axis cf rotation a distanceequal to the radius of the co-axial circle formed by the projections of the faces of the gear teeth, devices for simultaneously rotating each of said means in timed relation, means for adjusting the blank support to establish a definite distance relationship between its axis of rotation and the axis of rotation of the former, means for feeding the former into the blank by an increment of its radial distance from its axis of rotation, and means fr coordinating the operations of said devices whereby the gear forming operation is completed without varying said distance relationship.

6. Apparatus for forming ating, comprising, 1n combination a blan support and a former support rotatable on axes perpendicular to each other, said former support being fixed against axial displacement, devices whereby they are relatively movable Without changing the distance between said axes of rotation, and drivin mechanism for simultaneously rotating t e blank and former in timed relation.

7. Apparatus for forming worin gearing, comprising, in combination, a blank support and a former support rotatable on axes perpendicular to each other, said former support being fixed against axial displacement, means whereby they are relatively movable for forming purposes without changing the distance between said axes of rotation, and means for driving said elements in proper timed relation.

8. Apparatus, according to claim 5, wherein the forming means is composed of end cutters and intermediate cutters.

9. Apparatus for producing worm gearing, comprising, in combination, means for rotating a former and a blank simultaneously about two axes perpendicular to each other, and means for effecting the former feed by changing the relative rotative positions ofthe former and blank while maintaining a fixed distance between said axes.

10. The method of producing worm wheels which consists in providing a blank having tooth gaps of established depth, and sha ing the flanks by a bobbing operation in w ich the feed is introduced by changing the relative rotative positions of the hob and blank while maintaining a fixed distance between the axes of rotation.

11. The method of producing worm wheels which consists in rovidin a blank having tooth gaps of esta lished e th and widening) the gaps and finishing t e flanks with a ho having clearance with respect to the flanks, inwhicli the feed is introduced by changing the relative rotative positions of the hob and blank while maintaining a fixed distance between the axes of rotation. i

12. The method of producin Worm wheels which consists in mounting a lank and hob on axes perpendicular to each other, said hob Pfl presenting a thread section thinner than that presented by the corresponding worm, and ormin rou h cut tooth ga s of maximum depth y ucing the initial distance between the respective axes of rotation until said distance corresponds with the operative center distance of t e nished gear set, and subsequently widening the tooth gaps and finishing the tooth flanks by phanging the relative rotative position of the elements without changing the distance between said axes.

13. Apparatus for forming the complemental elements of worm gears, comprising blank supporting means jand former su porting means rotatable on axes perpen icular to each other, and resllonsive to a predetermined time relations ip, and means for inducing and controlling during rotation the cutting feed, while maintaining a fixed distance between said axes throughout the formin period, said worm member being restraine from movement in the direction of its axis.

14. Apparatus for forming worm wheels, comprising, in combination, blank supportin means and hob supporting means rotatab e on axes perpendicular to each other, and means for advancing and/or retractin either element about their respective axes o rotation while maintaining a fixed distance between the axes of rotation.

15. vApparatus for forming worm wheels, comprising, in combination, blank support- 'in means and hob supporting means rotatab e on axes perpendicular to each other, and means for relatively advancing and/or retractin said elements about their respective axes o rotation to effect flank forming while maintaining the predetermined timed relationshi and without interfering with the xed distance between said axes of rotation.

16. Apparatus for forming gearing, comprising in combination, a blank support and a former support rotatable on axes perpendicular to each other, said former support being fixed against axial displacement, means whereby they are relatively movable during rotation for forming purposes without changing the distance between the axes ofrotation, and means for drivin said 4elements in predetermined timed re ation,

17. The method of producing either elev ment of worm gear-in which consists in rotating a blank and a ormer about axes perpendicular to each other and in predetermined timed relationship and, durin the roughing operation to establish depth, introducin t e feed by decreasing the initial distance tween the axes of rotation until said distance corresponds substantially to that of the finished gear setaand then widening the gaps and imparting the finished form to the anks b advancing and retracting either element a out its axis of rotation therebyg inducing the necessa cuttin feed while maintainin during said finis ing o ration a fixed istance between centers o rotation.

18. The method of producing either element of worm gearing, which consists in rotating a blank avin rou h gaps of previously established dept an a former about axesl perpendicular to each other and in predetermined timed `relation and shaping the flanks by an o ration in which the feed is introduced in increments by relatively advancing and retractin the blank and former about an axis of rotation, while maintaining a fixed distance between said axes.

19.` The method of finishing either element of worm gearin which consists in rotatin a former and a blank in predetermined time relation about axes perpendicular to each other and imparting the final form to the Hanks by relatively oscillating the blank and former about an axis of rotation, for the purposeof inducinv the feed, while maintainin during the flan finishing operation a fixe distance between axes of rotation.

20. A paratus for producing either element o worm gearing, which consists in means for supporting a former and blank rotatable on axes perpendicular to each other, means for maintaining a predetermined timed relationship, means for introducing the feed and establishing depth by reducing the initial distance between axes of rotation', means whereby the gaps between adjacent flanks may be widened and the final flank form imparted by introducing a cutting feed and co-related means for controlling same by advancing and retracting the former or blank about its own axis of rotation, and means for retainin a fixed distance between the axes of rotation during the nishing trolled by relatively advancing and retracty ing the blank and former about an axis of rotation, and means for establishing and retaining a fixed distance between said axes throughout said operation.

22. Apparatus for finishing either element of worm gearing, which consists in means for rotating a former and blank about axes perpendicular to each other and in proper timed relation, means for actuating and controllin the oscillation of the former and/or the bla about an axis of rotation thereby inducing the required feed for the flank finishing operation, and means for maintaining a fixed distance between the axes of rotation throughout the operation.

23. Apparatus for producing worms, comprising, in combination, blank supporting means and forming means rotatable on axes perpendicular to each other, and means for changing the relative positions of the blank and forming means while maintaining a fixed distance between the axes of rotation.

24. Apparatus for finishing either element of worm gearing, which consists in providing a former of relatively thin cross section but o f accurate mating capacity and a blank previously roughed out to the desired depth, finishing stock however remaining on the Y flanks, means for supporting said former and lOS blank, and means for rotating same on axes perpendicular to each other and in predetermined timed ratio, means for introducing the feed by changing, as may be desired, the relative rotative positions of thc former and/'or blank about its axis of rotation, and means whereby the distance between said axes of rotation may be fixed throughout said finishing. operatlon.

25. Apparatus for producing either elet ent of worm gearing, which consists in providing a former Whose active cutting edges lie between parallel tangents to a coaxial circle defined by the extensions of the active cuttin edges and a blank, bothof which are rotata le on axes perpendicular to each other, means for changing their relative positions, and means for maintaining throughout the forming operation a fixed distance between said axes.

26. Apparatus for finishing either element of worm gearing, comprising blank supporting means and forming means rotatable on axes perpendicular to each other, means for driving said former and blank in any predetermined timed relationship, and means for introducing the feed in any desired inerements, by alternately advancing and retracting the former and /or blank angularly about their respective axes of rotation, and means for retaining a fixed distance between said axes of rotation throughout said finishing operation.

27. Apparatus for forming worm gear elements, comprising means for supporting a worm element, means for supporting a, worm wheel element, means for maintaining the distance between the axes of said supporting means constant, means for rotating said sup- 'portingmeansn a worm element on said worm supporting means, a Worm Wheel element on said worm wheel supporting means, one of said elements constituting a former and the other constituting the Work, said worm element being fixed against axial movement, and means for effecting a relative feed between said elements during rotation.

28. A method of producing Worm gearing including rotating a blank element and a former element in a timed relation about axes which are non-intersecting and non-parallel, and forming the blank element by changino the normal relative rotative positions of said elements while maintaining relatively fixed center distances of said axes.

29. A method of producing either element of globoidal gearing, consisting in rotating V a. blank element and a. former element in timed relation about axes perpendicular to each other, and forming the blank by changin the normal relative rotative posltions of said elements during rotation while maintaining relatively fixed centerndistances of said axes.

30. The method of finishing either element of globoidal gearing, comprising rotating a blank element and a former element about axes at right angles to each other in a predetermined timed relationship, and during said rotation angularly advancing o: retracting the normal relative rotative position of at least one of said elements while main-taining relatively fixed center distances of said axes. ,i

3l. The method of producing globoidal worm wheels consisting in rotating a hob and a wheel blank in timed relation on axes per: pcndieular to each other, and formin the wheel teeth by changing the normal reative rotative positions of said hob and blank while maintaining relatively fixed center distances of said axes.

The method of producing globoidal worm Wheels consisting in rotating a former and a wheel blank in timed relation on axes perpendicular to each other, and forming the Wheel teeth by changing the normal relative rotative positions of said former and blank While maintaining relatively fixed center distances of said axes.

33. Apparatus for producing either element of worm gearing comprising, in combination, means for rotating a blank element and a former clement on non-intersecting and non-parallel axes, means for driving the first mentioned means in timed relation, and means for introducing a cutting feed between said elements by changing the normal relative rotative position of one of said elements.

34. Apparatus for producing either element of globoidal gearing comprising, in combination, means for rotating a blank and a former in timed relation about axes perpendicular to each, and other means for changing the normal relative rotative positions of said elements, during rotation for former purposes.

35. Apparatus for producing either element of worm gearing comprising, in combination, means for rotating a blank and a former on axes perpendicular to each other, means for driving said elements in timed relation, means for varying the distance between said axes, and means for oscillating the former and/or blank about its axis of rotation.

36. Means for finishing either element of globoidal gearing, comprising, in combination, means for supporting a blank, means for supporting a former, means for rotating said means on axes perpendicular to each other and in timed relation to each other, and

a blank and the other one of which is adapted to support a former, said elements being mounted with their' axes in non-intersecting and non-parallel relationshi means for rotating said elements in time relation, means for varying the distance between said axes, and means for oscillatin at least one of said elements about its axis or feeding purposes. 38. Apparatus for producing ear elements comprising a pair of rotatable s pporting elements one of which is adapted to sup ort a blank and the other one of which is a apted to support a former, said elements being mounted with their axes in non-intersecting and nonarallel relationship means for rotatig sai elements in timed relation, and l; means for effecting a cutting feed between said blank and former comprising means for varying the distance between said axes, and means for oscillating one of said elements about its axis. a zo 39. The method of producing by bobbing,

globoidal Worm wheels of substantial mat- 1n capacity, which consists in providing a hoi identical with the worm as to relat1ve mating capacity and having cutting edges lying and operating within surfaces common in form to those of the thread ianks of the worm with which the wheel is to mate, opposing ilanks of the hob being arran ed m such manner as to represent .threads t inner 3o than those of the worm, providing a Vwheel blank, rotating said elements about axes perpendicular to each other, and widening the tooth gap by advancing and retractin the relative positions of the hob and wheel lank r'. while maintaining fixed centers of rotation in conformity with those of the finished gear set.

40. The method of producin globoidal worm wheels, which consists in orming the 43 Ytooth Hanks by-'a two-stage bobbing operation whereof the secondis a yfinishin operation, and during said finishing operation shaping the flanks with a hob whose threads are thinner than the worm threads and under side l 45 feed while maintaining proper time and position relationship. e

41. The method of producing worm wheels to cooperate with worms of the envelopin type, which consists in providing a ho having threads of relatively thin cross section as compared to the corresponding worm, providing a wheel blank, said elements being 'mounted on axes perpendicular to each other and the distance between the axes of rotation 55 of said elements corresponding to the center distance of the gear set during the time that the final form is being imparted to the wheel flanks, an angular shift iirst in one direction and then the other being imparted to either f3 the hob or work piece about its'res ective axis in order to provide the required wldth of .tooth ap and to insure a tooth flank form, followxn the natural conformity I, of the worm ank, in its passage through the wheels.

vthe :former and lank durin rotation, and a Leonesa 42. The method of producing globoidal worm wheels, which consistsn in orming the tooth flanks with hobs whose active cutting edges lie entirely within a definite base circle, one or more of said cutting ed es at each end of said hob being positione substantially at right angles to the hob axis and when extended being tangent to said base circle.

43. The method of producin globoidal worm wheels, which consists in orming the tooth iianks with hobs of relatively 'thin cross section whose active cutting edges lie entirely within a vdefinite base circle, one or more of said cutting edges at each end of said hob being positioned substantially at right angles to the hob axis and when extended bein tan ent to said base circle, and tinishing t e w eel tooth Hanks while maintaining tV etpredetermined center distance of the ar se 44. The method of producin worm wheels to cooperate with worms of t e enveloping type, by operating with a hob having threads thinner in cross section than the corresponding wormv threads and presenting cutting edges so arranged that when the opposed edges are extended in a plane, passing througih the axis of said hob, the angle so forme diiers from the corresponding angle 05 on the worm, but nevertheless having the prodperty 'in common with said worm that sai edge projections when taken in a plane passing through the axis of the hob, are tangent to the samebase circle, whereby finishlng of the wheel teeth ianks is possible while maintaining the predetermined center distance of the gear set.

45. Apparatus for forming earing,-com prising', m combination, bla supporting means and forming means rotatable on axes perpendicular to each other, said forming means being fixed against axial displacement means for chan g the relative positions o system of control for establishing and maintainln throughout the forming operation a.

' fixed ance between said axes.

46. Apparatus for forming worm gearing, comprising, in combination, 'a blank support 11? and a former support rotatable on axes perpendicular to each other, said former support being iixed against axial displacement, means whereby they are relatively movable for generating purposes without changing the distance between said axes o'f rotation, and means for driving said elements in proper timed relation.

47. The method of machining teeth on a gear blank, which includes the steps of mountinga former and blank on independently rotatable axes, of providing teeth on the former of less width than the ultimate gap to be formed in the blank, of providing cutting edges on each side of the teeth, and 130.

of advancing first one cutting ed 1,es5,ese

and then the other into opposite sides of v e ga inltially formed to widen the ap a pre etermined amount and to finish t e sides thereof.

48. The method of machinin teeth on a gear blank, which includes e steps of mounting n former and blank in forming relation to each other, of providing teeth on the former of less width than the ultimate gap to be formed in the blank, of providing cutting edges on each side of the teeth, and of eecting a relative advancement between one cuttin edge and a side of the gap and thereafter tween the opposite cutting ed ald the opposite side of the gap to form sind s1 es.

In testimony whereof I aix m si SAMUEL ature. NE.

CERTIFICATE 0F CRRECTION` Patent No.` 1,885, 686.

November l, i932,

SAMUEL L; conn lt is hereby'certfied that the name of the assignee in the above` numbered patent was erroneously described and specified as "Cone Worm' Gearing Cor.- poration" whercas'slid name should have been described and specified as "Cone lor. Gear Corporation" as shown by the records of as signmenis in this office; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of ther case in the Patent Office` Signed and sealed this glut day of February, A. l).Y 1933.

y Y' (Sc-l) Acting Clonl'iissionei' of Patents.

of advancing first one cutting ed 1,es5,ese

and then the other into opposite sides of v e ga inltially formed to widen the ap a pre etermined amount and to finish t e sides thereof.

48. The method of machinin teeth on a gear blank, which includes e steps of mounting n former and blank in forming relation to each other, of providing teeth on the former of less width than the ultimate gap to be formed in the blank, of providing cutting edges on each side of the teeth, and of eecting a relative advancement between one cuttin edge and a side of the gap and thereafter tween the opposite cutting ed ald the opposite side of the gap to form sind s1 es.

In testimony whereof I aix m si SAMUEL ature. NE.

CERTIFICATE 0F CRRECTION` Patent No.` 1,885, 686.

November l, i932,

SAMUEL L; conn lt is hereby'certfied that the name of the assignee in the above` numbered patent was erroneously described and specified as "Cone Worm' Gearing Cor.- poration" whercas'slid name should have been described and specified as "Cone lor. Gear Corporation" as shown by the records of as signmenis in this office; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of ther case in the Patent Office` Signed and sealed this glut day of February, A. l).Y 1933.

y Y' (Sc-l) Acting Clonl'iissionei' of Patents. 

